[clang-tools-extra] [clang-tidy] bugprone-implicit-widening ignores const exprs that fit (PR #98352)

[Piotr Zegar via cfe-commits]

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@@ -0,0 +1,56 @@
+// RUN: %check_clang_tidy %s bugprone-implicit-widening-of-multiplication-result %t -- \
+// RUN:     -config='{CheckOptions: { \
+// RUN:         bugprone-implicit-widening-of-multiplication-result.IgnoreConstantIntExpr: true \
+// RUN:     }}' -- -target x86_64-unknown-unknown -x c++
+
+long t0() {
+  return 1 * 4;
+}
+
+unsigned long t1() {
+  const int a = 2;
+  const int b = 3;
+  return a * b;
+}
+
+long t2() {
+  constexpr int a = 16383; // ~1/2 of int16_t max
+  constexpr int b = 2;
+  return a * b;
+}
+
+constexpr int global_value() {
+  return 16;
+}
+
+unsigned long t3() {
+  constexpr int a = 3;
+  return a * global_value();
+}
+
+long t4() {
+  const char a = 3;
+  const short b = 2;
+  const int c = 5;
+  return c * b * a;
+}
+
+long t5() {
+  constexpr int min_int = (-2147483647 - 1); // A literal of -2147483648 evaluates to long
+  return 1 * min_int;
+}
+
+unsigned long n0() {
+  const int a = 1073741824; // 1/2 of int32_t max
+  const int b = 3;
+  return a * b;
+  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: performing an implicit widening conversion to type 'unsigned long' of a multiplication performed in type 'int'
+  // CHECK-MESSAGES: :[[@LINE-2]]:10: note: make conversion explicit to silence this warning
+  // CHECK-MESSAGES:                  static_cast<unsigned long>( )
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PiotrZSL wrote:

actually you should use CHECK-FIXES for this.

https://github.com/llvm/llvm-project/pull/98352